Most patients with Crohn’s Disease (CD) face nutritional challenges as numerous foods can trigger CD symptoms. It is one of the most common inflammatory bowel diseases and requires a special diet.
“Inflammatory bowel diseases (IBD) are chronic inflammatory diseases involving potentially the entire gastrointestinal tract. Most often, the onset of IBD is during young adulthood, but in 15-20% of patients the disease starts before their 18th anniversary. Based on clinical, endoscopic, but also immunological and biological parameters, different phenotypes of IBD can be identified. Usually, the presence of granulomatous lesions and/or the involvement of the small bowel with typical ulcerations orientate towards the diagnosis of Crohn’s disease (CD), while isolated continuous colonic involvement is in favor of ulcerative colitis (UC). […] Thus, treatment strategies aim to control this chronic inflammatory process and are mainly based on immunosuppressive agents; however, there are clear indicators that nutritional interventions might also play an important role in controlling IBD.”1
“In distinction, CD (Crohn’s Disease) can involve any part of the GI tract and can present in a penetrating (fistulizing), fibrostenotic (stricturing), or inflammatory pattern, and usually has a clinical presentation of diarrhea, abdominal pain, and malnutrition. Surgical resection of the affected bowel segments is a short-term solution that is rarely curative and in the long run can lead to detrimental complications such as short gut syndrome and total parenteral nutrition (TPN) dependency.”2
How Fiber Affects Crohn’s Disease Patients
Fiber is a type of carbohydrate that the body is unable to digest. Most carbohydrates decompose into sugar molecules but fiber does not.
“Dietary fiber intake provides many health benefits. A generous intake of dietary fiber reduces risk for developing the following diseases: coronary heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal disorders. Furthermore, increased consumption of dietary fiber improves serum lipid concentrations, lowers blood pressure, improves blood glucose control in diabetes, promotes regularity, aids in weight loss, and appears to improve immune function. Unfortunately, most persons in the United States consume less than half of the recommended levels of dietary fiber daily. This results from suboptimal intake of whole‐grain foods, vegetables, fruits, legumes, and nuts. Dietary fiber supplements have the potential to play an adjunctive role in offering the health benefits provided by high‐fiber foods.“3
Regarding Crohn’s disease, fiber provides multiple health benefits, like normalize bowel movements. However, not all types of fiber are favorable for Crohn’s Disease, as some patients find them difficult to digest and occasionally worsen their symptoms. Recent studies demonstrate that soluble fruit fibers are the most beneficial for preventing CD and flare-ups.
“Dietary fiber has been investigated as a means of increasing short-chain fatty acid (SCFA) production. IBD (inflammatory bowel disease) has been linked with impaired SCFA production. SCFAs are mainly produced by the anaerobic bacterial fermentation of undigested carbohydrates and fiber polysaccharides. In 1995, Galvez et al reviewed a number of studies that concluded that dietary fiber confers clinical benefits in patients with IBD because it maintains remission and reduces colonic damage. This is thought to occur by increasing SCFA production and by altering the gut flora towards predominantly non-pathogenic bacteria.”4
“Dietary fiber is known to 1) improve laxation by increasing bulk and reducing transit time of feces through the bowel; 2) increase excretion of bile acid, estrogen, and fecal procarcinogens and carcinogens by binding to them; 3) lower serum cholesterol; 4) slow glucose absorption and improve insulin sensitivity; 5) lower blood pressure; 6) promote weight loss; 7) inhibit lipid peroxidation; and 8) provide anti-inflammatory properties. After a large prospective cohort study, Park et al found that dietary fiber intake was significantly inversely associated with risk of total death and death from cardiovascular disease, infectious diseases, and respiratory diseases in both men and women. Dietary fiber intake was also related to a lower risk of death from cancer in men. Among specific sources of dietary fiber, fiber from grains showed the most consistent inverse association with risk of total and cause-specific death. Namely, current chronic diseases are related to decreased consumption of dietary fiber—which is a part of dietary Westernization. In evaluating the effects of dietary Westernization we are apt to stress adverse effects of increased consumption of animal protein or animal fat, but it is equally important to stress the drawbacks of decreased consumption of dietary fiber.”5
Types of Dietary Fiber
“DF can be separated into two basic types based on its properties and effects on the body. These two types are insoluble and soluble fiber. Insoluble fibers, such as cellulose, hemicellulose, and lignin, do not dissolve in water. Insoluble fibers are found in foods such as wheat bran, whole grains, and vegetables. Insoluble fibers absorb water and increase the intestinal bulk, which helps the intestine function properly. Soluble fibers, such as gum and pectin, dissolve in water and are found in beans, oats, barley, some fruits, and vegetables. Soluble fibers may play a role in lowering blood cholesterol and in regulating the body’s use of sugar. Plant foods are the only source of dietary fiber. The best sources of fiber are whole-grain bread and cereals, fruits and vegetables, and dried beans and peas. These foods provide both soluble and insoluble fibers.”7
Soluble fiber helps lower cholesterol and glucose levels and assists with bowel movements. Fruits like pears, pineapple, apples, raisins, grapes, blueberries, strawberries, and plums have a high content of soluble fiber. Also, nuts, beans, lentils, oatmeal, and oat cereals. Soluble fiber can become pasty after absorbing water, similar to adding water to oatmeal.
Insoluble fiber prevents constipation and lowers glucose and blood cholesterol levels. Vegetables like sweet potato, asparagus, broccoli, cabbage, carrots, corn, and cucumbers. Also beans, whole grains, and whole wheat (verify the nutritional facts label for bread and cereal information). Insoluble fibers cannot absorb water, similar to adding water to corn.
Causes of Flare-Ups and Other Complications
Raw foods can trigger some patients’ flare-ups as they are harder to digest. Consequently, cooked vegetables and soluble fiber fruit diets tend to reduce and prevent CD symptoms. Cease fiber consumption when there is an intestinal blockage.
“Dietary fibers affect the entire gastrointestinal tract from the mouth to the anus. High-fiber foods usually have lower energy density and take longer to eat. Soluble fibers usually delay gastric emptying. Soluble fibers may act to slow transit of food materials through the small intestine while insoluble fibers tend to create “intestinal hurry”. In the small intestine, dietary fibers can elicit responses of a wide variety of gastrointestinal hormones that serve as incretins to stimulate insulin release and affect appetite. Some fibers bind bile acids and impede micelle formation, thus increasing fecal excretion of bile acids and cholesterol.56 In the colon, fermentable fibers increase bacterial mass with some acting as prebiotics to promote health-promoting bacteria such as lactobacilli and bifidobacteria. Insoluble fibers are especially effective in increasing fecal mass and promoting regularity.”9
The Role of Fibers in Crohn’s Disease Prevention
Multiple studies have concluded that soluble fiber, more specifically soluble fruit fibers, helps prevent or reduce the risk of developing Crohn’s Disease (CD).
”The possible roles of dietary fibers (DFs) in the etiology of CD (Crohn’s Disease) and UC (ulcerative colitis) are unclear. Diets low in DF (low residue diets) are sometimes recommended to patients with the active forms of the diseases, while recommendations for patients with the inactive forms have usually not considered dietary fiber, partly because individuals differ in dietary tolerances and intolerances. Different types of DF have different properties and health effects in diseases such as IBD. Potential benefits include reducing diarrhea or constipation, producing short-chain fatty acids (SCFAs), down-regulating inflammation, promoting tissue healing, and by these means potentially preventing the onset of colorectal cancer (CRC) in susceptible IBD patients.”10
“Although the precise mechanism is to be determined, epidemiology provides convincing evidence that a plant-based diet is a healthy diet providing therapeutic and/or preventive effects against current major chronic diseases. Available data suggest the rationale to use dietary fiber in the treatment of IBD (Inflammatory bowel diseases). We believe a plant-based diet not only is effective for gut inflammation but also promotes the general health of IBD patients. A plant-based diet inevitably contains considerable amounts of dietary fiber. A high amount of dietary fiber is not harmful and seems to be favorable for CD.”11
The evidence concludes that most dietary fibers are beneficial for Crohn Disease patients. As plant-based carbohydrates, they reach the large intestine or colon, since the small intestine cannot digest them. Moreover, they assist in the management of blood sugar and appetite. Consult a specialist to discuss particular nutritional requirements if you have Crohn’s Disease.
(1) Role of Diet in Inflammatory Bowel Disease. Ruemmele, F.M. Annals of Nutrition & Metabolism. 2016. https://www.karger.com/Article/FullText/445392
(2) Advances in the Diagnosis and Management of Inflammatory Bowel Disease: Challenges and Uncertainties. Mosli, M., Beshir, M.A., Al-Judaibi, B., Al-Ameel, T., Saleem, A., Bessissow, T., Ghosh, S., & Almadi, M. The Saudi Journal Of Gastroenterology. 2014. http://www.saudijgastro.com/article.asp?issn=1319-3767;year=2014;volume=20;issue=2;spage=81;epage=101;aulast=Mosli
(3, 8) Health benefits of dietary fiber. Anderson, J.W. Baird, P., Davis, R.H., Ferreri, S., Knudtson, M., Koraym, A., Waters, V. & Williams, C.L. Nutrition Reviews. 2009. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1753-4887.2009.00189.x
(4) Role of diet in the management of inflammatory bowel disease. Rajendran, N. & Kumar, D. World Journal Of Gastroenterology. 2010. https://www.wjgnet.com/1007-9327/full/v16/i12/1442.htm
(5, 6, 11) High Amount of Dietary Fiber Not Harmful But Favorable for Crohn Disease. Chiba, M., Tsuji, T., Nakane, K. & Komatsu, M. The Permanente Journal. 2015. http://www.thepermanentejournal.org/issues/2015/winter/5802-crohns-disease.html
(7) Dietary fibre and human health. Rana, Vikas & Bachheti, R. & Chand, Tara & Barman, Anjan. International Journal of Food Safety Nutrition and Public Health. 2012. https://www.researchgate.net/publication/235978852_Dietary_fibre_and_human_health
(8, 10) Potential Benefits of Dietary Fibre Intervention in Inflammatory Bowel Disease. Wong, C., Harris, P.J. & Ferguson, L.R. International Journal of Molecular Science. 2016. https://www.mdpi.com/1422-0067/17/6/919/htm